Growing Onion

Allium cepa : Amaryllidaceae / the onion family

Jan F M A M J J A S O N Dec
  S                    
    P P                

(Best months for growing Onion in USA - Zone 5a regions)

  • S = Plant undercover in seed trays
  • P = Sow seed
  • Easy to grow. Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 46°F and 86°F. (Show °C/cm)
  • Space plants: 2 - 4 inches apart
  • Harvest in 25-34 weeks. Allow onions to dry before storing.
  • Compatible with (can grow beside): Lemon Balm, Borage, Carrots, Beets, Silverbeet, Lettuce, Amaranth
  • Avoid growing close to: Peas, Beans

Your comments and tips

07 May 17, (Australia - sub-tropical climate)
Hello Jimmy, We need a bit more information. Do you want to sell the onions while they are small or when they are larger, before the tops die down. You can sell or eat onions at any stage but if the tops have not died down they will not keep very long.
04 May 17, Paul (Australia - temperate climate)
How deep do you plant the onion seedling if you buy a small tray from a garden centre or Bunnings?
06 May 17, Sean (Australia - sub-tropical climate)
Onion seedlings from punnets are usually very small.Make a V shaped trench abut 50 mm (2") deep and lay them along one side of the trench at recommended spacing (probably 100 mm (4") then carefully draw the soil from the other side of the trench over the base of the seedlings. This is best done on a cool overcast day or in the evening as a warm sunny day will stress the little seedlings too much. They might stay laying down for a few days but will soon be upright.
22 Apr 17, Keikantseng (South Africa - Summer rainfall climate)
I an staying in Taunton village in North west province. Can I plant onion in April?
23 Apr 17, John (Australia - temperate climate)
Yes you can. Long Keeping varieties can be sown now.
18 Apr 17, gayle (Australia - temperate climate)
Hi...I have planted brown onion seeds in seed trays a week ago..they are sprouting...I was wondering when do I plant them in the vegetable garden. Also can I plant seed potatoes now (April) in Victoria. Thanks.
19 Apr 17, Giovanni (Australia - temperate climate)
Onion seedlings are susceptible to danping off so make sure they are in a well aired place. They can be transplanted as soon as they are large enough (2 or 3 leaves). The smaller they are the more attention they will need in the ground so wait a while, they will be easier to transplant and with less transplanting shock.
15 Apr 17, Jack (Australia - sub-tropical climate)
I've been looking for white onions for some time . Is there any reason for the short supply ?
15 Apr 17, Jo (Australia - temperate climate)
Do you mean white long-keeper, or white salad onions. Both types should be readily available on-line from companies like - New Gippsland Seeds, The Seed Collection, Diggers, Green Harvest and Eden seeds.
11 Apr 17, nik (New Zealand - temperate climate)
I planted 50 red onion seedling last year and they all split into 3 or 4 more like shallots, so after 6 months I gave up and pulled them out What went wrong ? there is no red shallot variety is there?
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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. Gardenate is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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